package com.kt.cart.interceptor;

import com.kt.cart.to.UserInfoTo;
import com.kt.common.constant.AuthServerConstant;
import com.kt.common.constant.CartConstant;
import com.kt.common.vo.MemberRespVO;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import org.thymeleaf.util.StringUtils;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.UUID;

/**
 * @program: e-mall
 * @description: 购物车拦截器
 *               在执行目标方法前，判读用户的登录状态。并封装传递给controller目标请求
 * @author: KamTang
 * @create: 2022-01-17 09:36
 **/
public class CartInterceptor implements HandlerInterceptor {

    // 1、快速得到用户信息，id，user-key -- ThreadLocal-同一个线程共享数据
    public static ThreadLocal<UserInfoTo> threadLocal = new ThreadLocal<>();

    /**
     * 业务执行之前
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        UserInfoTo userInfoTo = new UserInfoTo();
        HttpSession session = request.getSession();
        MemberRespVO memberRespVO = (MemberRespVO) session.getAttribute(AuthServerConstant.LOGIN_USER);
        if (memberRespVO != null) {
            // 用户登录了
            userInfoTo.setUserId(memberRespVO.getId());
        }
        Cookie[] cookies = request.getCookies();
        if (cookies != null && cookies.length > 0) {
            for (Cookie cookie : cookies) {
                String cookieName = cookie.getName();
                if (cookieName.equals(CartConstant.TEMP_USER_COOKIE_NAME)) {
                    userInfoTo.setUserKey(cookie.getValue());
                    userInfoTo.setTempUser(true);
                }
            }
        }
        // 如果没有临时用户一定需要分配一个临时用户
        if (StringUtils.isEmpty(userInfoTo.getUserKey())) {
            // 需要自动为其分配一个user-key
            String uuid = UUID.randomUUID().toString();
            userInfoTo.setUserKey(uuid);
        }
        // 目标方法执行之前
        threadLocal.set(userInfoTo);
        return true;
    }

    /**
     * 业务执行之后；分配临时用户，让浏览器保存。
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        UserInfoTo userInfoTo = threadLocal.get();
        // 如果没有临时用户，一定保存一个临时用户
        if (!userInfoTo.isTempUser()) {
            Cookie cookie = new Cookie(CartConstant.TEMP_USER_COOKIE_NAME, userInfoTo.getUserKey());
            cookie.setDomain("gulimall.com");
            cookie.setMaxAge(CartConstant.TEMP_USER_COOKIE_TIMEOUT);
            response.addCookie(cookie);
        }
    }
}
